Spark-plug



J. L. HILL.

SPARK PLUG.

APPLICATION FILED NOV. 26. ms.

Patented Sept; 2, 1919.

8' OH L. HILL, OF TEXAS CITY, TEXAS.

SPARK-PLUG.

Specification of Letters Patent.

Patented Sept. a, rare.

Application filed November 26, 1915. Serial No. 63,513.

To all whom 2'25 may concern:

Be it known that 1, JOHN L. HILL, a c1t1- zen of the United States, residing at Texas City, in the county of. Galveston and State of Texas, have invented a new and useful Spark-Plug, of which the following is a specification.

My present invention relates to spark plugs, in which one electrode 1s movable with respect to the other electrode or electrodes.

The principal object of my invention is to provide a spark plug whlch may, at all times, be maintained operative by the cleaning of the sparking faces of the electrodes while the plug is in use.

Another object of the inventlon 1s to provide a plug whereby the intake and compression, and power and exhaust strokes of the engine will reciprocate certain elements, one of which is an electrode, to elfectlvely clean the electrodes after each ignition of the charge, thereby removing foreign matter from the sparking faces.

Other objects are to provide a spark plug which is inexpensive to manufacture and assemble; which will remain in good repair for a considerable length of time; and, which may be manually operated to demonstrate its practicability or to place the elec trodes in sparking condition wlthout removing the spark plug from the englne or rotating-the engine shaft.

Other objects of the invention Wlll appear in the following detailed description, taken in connection with the accompanying drawing, forming a part of this specification, and in which drawing:

Figure 1 is a longitudinal sectional view through a spark plug constructed according to my invention.

Fig. 2 is a view similar to Fig. 1, assuming that the plug has been given a quarter bodily turn. Y

Fig. 3 is a bottom plan view of the plug. Fig. 4 is a sectional view on the line 4-4 of Fig. 2. r i

In the drawings, where similar characters refer to similar parts throughout the several views, A designates an outer shell; B means for providing a bore C within, but insulated from the shell A; D reciprocal elements movable in said bore; and, E an element for cleaning one of the electrodes and limiting the movement of elements D in one direction.

Referring first to the outer shell A, it is of theusual type, provided with a wrench head 5, screw headed portion 6 to be turned into the engine body, internal screw thread 7 Within said wrench head and reduced internal bore 8 providing a shoulder 9.

Concerning the means B, in addition to comprising the usual body 10 of insulating material and the nut 11 having screw threaded engagement with thread 7, holding the enlargement 12 of body 10 firmly upon the shoulder 9, it includes a metallic sleeve 13' fitting within the bore 1 1 of body 10. The internal periphery of body 10 is en,- larged as at 15, intermediate its ends, while the sleeve 13 is provided with an enlargement 16 fitting into the peripheral enlargement l5, as clearly shown in Figs. 1 and 2. This arrangement may be brought about by forcing the sleeve 13 into the bore 14 of body 10 and expanding the lower end thereof so that the internal periphery of the enlargement 16 is alined with the lower portion of the bore 14. By this construction a shoulder 17 is provided in sleeve 13 for the purpose hereinafter to be set forth.

The upper end of sleeve 13 preferably ex tends beyond the end of body 10 and is screw threaded as at 1.8, to receive nut 19, and binding nut 20, between which may be secured a conductor of the ignition system.

As to the reciprocal elements D, they are slidable within the bore C, and comprise a piston 21, slidable within the enlargement 16 ofsleeve 13 and the lower portion of body 7 10; a stem 22 extending from. piston 21, through the main body'portion of sleeve 13 and exteriorly of the spark plug; and, a stem like electrode carried by and projecting from the other end of piston 21. If desired piston rings 24: may be provided about piston 21 and a suitable abutment 25 intermediate the sparking face of the electrode 23 and piston 21. The piston 21 stem 22 and electrode 23 all have a common axis-and it is to be ohserved that, by grasping the upper portion of stem 22 all of these elements may bereciprocated manually.

' myself limited to this particular construction, excepting in so far as the claims import. The electrodes 26 pass through perforations 27 in the upright arms 28 of. the

U-shaped spider, and may be of platinum or other suitable material, secured in place as by sweating. The base 29. of the U-shaped spider is perforated at 30 and is spaced from the bottom of shell A at. a distance sufficient to prevent its serving as an electrode When the piston 21 is uppermost, yet it serves as'a stop for movement of the piston in one direction, as by abutment 25 engaging the upperface of base 29. The perforation is of such a size as to receive the electrode 23, as piston 21 moves downwardly, and in this way, foreign matter is effectively removed from the sparking face of the electrode.

The sparking faces 31 of the; electrodes 26 may be concave, as clearly shown in Fig.

4, and are alined with. the internal wall of bore 0 so that, as piston 21 moves downwardly, and prior to the engagement of abutment 25 With base 29, any foreign matter is wiped from the sparking faces 31 by the piston. Abutment 25 may be of such a length as to prevent the piston from moving sufliciently to expose the piston ring 24 which might permit it to expand.

The operation of the plug is as follows; assuming :that the lower face of piston 21 is in communication with the firing chamber of an internal combustion engine, when ever the engine is under compression, the piston is forced until its upper end engages abutment 17 in which position the electrode 23 is in operative relation to the electrodes 26, however, during an intake stroke the piston 21 is moved toward element E, at times, augmented by the force of gravity, and the electrodes are effectively cleaned of foreign matter, as hereinbefore described.

If desired, the upper portion of stem 22 may be grasped and a reciprocatory movement imparted to the other movable elements, thereby effectively cleaning the electrodes or demonstrating the practicability of the invention, without operating the engine.

Changes in details may be made without departing from the spirit of my invention; but,

I claim:

1, In a spark plug, the combination of an outer metallic shell, means rigid with said outer shell providing a bore within but insulated from said outer shellfan electrode in comluctinjg conununication with said outer shell and having its sparking face in alinement with the inner face of the wall of said bore, and a piston of substantially uniform diameter slidable in said borc,ac-

tuated by the intake and compression strokes of the'engine, and having an amplitude of reciprocation sufficient to rub against the said sparking face thereby wiping foreign matter from the said face during reciprocation of the piston. 7

2. A sparking plug comprising in combination, an outer shell provided with a perforated U-shaped spider at its lower end, means providing a bore within but insulated from said outershell, axially alined with the said perforations, electrodes'carried by the upright arms of said spider, disposedwith their sparking faces alined with the inner face of the wall of said bore, a piston in said bore having an amplitude of reciprocation sutlicient to rub against the said sparking faces, and an electrode coaxial and movable with said piston disposed to extend through the said perforations in the said spider during movement of said piston toward said spider, said last mentioned electrode of a diameter relative to the diameter of said perforations, so as to come in Wiping engagement with said spider at its circunrferential face.

3. A spark plug comprising in combina tion, an outer shell, a body of insulating material carried by said shell and having a bore with its internal periphery enlarged intermediate the ends, a sleeve of conductmg material within said bore having an enlargement embedded in said peripheral en largement, the bore of said sleeve at said enlargement. thereof being alined with the bore of said body, a piston slidable in the bores of said sleeve enlar ement and body. a stem extending from one end of said pis ton through said sleeve and exteriorly of said body and outer shell, an electrode at. the opposite end of said piston, an electrode carried by said shell, and an element carried by said shell havinga perforation .in which said first mentioned electrode may move upon reciprocation of said piston, substantially as and for the purpose set forth.

4;. A spark plug comprising in combina tion, an. outer metallic shell, a plurality of stationary electrodes in conducting communication therewith. a movable electrode. means permitting movement of said last mentioned electrode into and out of sparking relation to said stationary electrodes,

electrodes.

I JOHN T... HILL. 

